Objectives To evaluate the effects of tea catechin inhalation on methicillin-resistant Staphylococcus aureus (MRSA) in disabled elderly patients. Design Seven days, randomized, prospective study. Setting Three hospitals in Japan. Participants Seventy-two patients aged 78 ± 11 years (mean age ± standard deviation) with cerebrovascular diseases, classified as disabled according to the activity of daily living and were either bedridden or required assistance for standing, and showing presence of MRSA in sputum. Interventions Inhalation of 2 mL tea catechin extract solution along with saline (3.7 mg/mL catechins, 43% of catechins are composed of epigallocatechin gallate), or saline alone, 3 times daily using a handheld nebulizer for 7 days. Measurements The endpoint of efficacy was the reduction rates of MRSA in sputum. The safety measure was the adverse events observed during the 7 days of inhalation. Results The reduction rates calculated as the summation of decrease and disappearance of MRSA in sputum at 7 days were 47% (17 of 36 patients) in the catechin group and 15% (5 of 33 patients) in the control group; the difference in the reduction rates between the 2 groups was statistically significant (P = .014). The disappearance rate of MRSA in sputum was higher in the catechin group (31%; 11 patients) when compared with the control group (12%; 4 patients), however the difference in the disappearance rate between the 2 groups was not statistically significant (P = .091). No adverse events, such as respiratory tract obstruction, allergic bronchial spasm, or skin eruption, including laboratory changes, were observed during the study. Conclusion The catechin inhalation appeared to reduce the MRSA count in sputum. However, the application of tea catechin inhalation as a supplementary treatment for controlling MRSA infection remains controversial.